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It may contain incorrect information, particularly with respect to dosage, duration, subjective effects, toxicity and other risks.

Summary sheet: 4-FMA
Chemical Nomenclature
Common names 4-FMA
Substitutive name 4-Fluoromethamphetamine
Systematic name 1-(4-Fluorophenyl)-N-methylpropan-2-amine
Class Membership
Psychoactive class Stimulant / Entactogen
Chemical class Amphetamine
Routes of Administration

WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section.

Threshold Common Heavy
10 - 25 - 50 - 100 - 125 mg
Light Strong
Threshold 10 - 25 mg
Light 25 - 50 mg
Common 50 - 75 mg
Strong 100 - 125 mg
Heavy 125 mg +
Total 4 - 8 hours
Onset 20 - 40 minutes
Come up 20 - 40 minutes
Peak 2 - 5 hours
Offset 1 - 2 hours
After effects 3 - 12 hours

DISCLAIMER: PW's dosage information is gathered from users and resources for educational purposes only. It is not a recommendation and should be verified with other sources for accuracy.

4-Fluoromethamphetamine (also known as 4-FMA) is a lesser-known novel stimulant-entactogen substance of the amphetamine class. 4-FMA is chemically related to 4-FA and methamphetamine. Little is known about its pharmacology, but it likely produces its effects by increasing levels of dopamine, norepinephrine, and serotonin in the brain.

4-FMA was first detected being sold in Japan as a legal high in 2006.[1] It has been sold online as a research chemical alongside 2-fluoroamphetamine (2-FA), 3-fluoroamphetamine (3-FA) and 4-fluoroamphetamine (4-FA).[2][3]

User reports describe the effects of 4-FMA as having characteristics of both traditional stimulants like amphetamine and entactogens like MDMA. Its effects have been described as subjectively lying between 4-FA and 2-FMA. It has been reported to be more likely to produce side effects like headaches and cardiovascular effects than similar substances.

Very little is known about the pharmacological properties, metabolism, and toxicity of 4-FMA. 4-FMA use may produce dependence and abuse as well as damage to the brain and other organs. It is highly advised to use harm reduction practices if using this substance.


4-Fluoromethamphetamine (4-FMA) is a synthetic molecule of the substituted amphetamine family. Molecules of this class contain a phenethylamine core featuring a phenyl ring bound to an amino (NH2) group through an ethyl chain with an additional methyl substitution at Rα. The term "amphetamine" is the contracted form of alpha-methylphenethylamine. 4-fluoromethamphetamine contains a fluorine atom at R4 of its phenyl ring and is therefore a fluorinated analogue of methamphetamine.


Similar to its structural analog 4-FA, 4-Fluoromethamphetamine is thought to act as a releasing agent and reuptake inhibitor of dopamine, serotonin, and norepinephrine, producing stimulating amphetamine-like effects at lower doses and more euphoric, entactogen effects similar to MDA at dosages above 125mg. [avoid opinion] Researchers have found some evidence that indicates some similarities between the "Serotonin Release" of 4-FMA and other popular empathogens such as: MDA, 4-Methylmethcathinone, and 4-fluoroamphetamine. [4].

The mechanism of action of 4-FMA effectively boosts the levels of the norepinephrine, dopamine, and serotonin neurotransmitters in higher doses in the brain by binding to and partially blocking the transporter proteins that normally clear these monoamines from the synaptic cleft. This allows dopamine, norepinephrine, and serotonin to accumulate within various regions of the brain, including its reward pathways, resulting in stimulating, euphoric and entactogenic effects.[5][6][7].

Subjective effects

In low doses, 4-FMA has been reported to be a lackluster nootropic for general productivity.[citation needed] Such usage would be strongly discouraged however, due to the increased risks for neurotoxicity and other dangerous side-effects. The reasoning for this warning is based on the studies showing that 4-FMA is similar to MDA, and belongs to the entactogen class. Using any entactogen frequently is considered dangerous, and it is seen as unwise to take "microdoses" below the minimum dose required to experience a "roll" with members of the entactogen class. At higher dosages, it is known to become dysfunctional and recreational due to the scattering quality of its euphoria and stimulation.[citation needed]

Similar to MDA, MDMA, 4-FA, and other substances that produce distinct pleasurable tactile "roll"-like sensations, which is typically linked to serotonin-releasing properties, 4-FMA has been reported to be able to produce similar entactogenic effects in addition to traditional stimulant ones. Some reports suggest it tends to come with more side effects and bodily strain than other fluorinated amphetamines, explaining its lack of popularity and availability.[8]

The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWiki contributors. These effects should be taken with a grain of salt and will rarely (if ever) occur all at once, but heavier doses will increase the chances of inducing a full range of effects. Likewise, adverse effects become much more likely on higher doses and may include serious injury or death.

Physical effects

Cognitive effects

After effects
Aftereffects (3).svg

Experience reports

Anecdotal reports which describe the effects of this compound within our experience index include:

Additional experience reports can be found here:

Toxicity and harm potential

Do not use 4-FMA if you have a history of heart-related issues or experience severe headache after its use. We have been made aware of a report released by Trimbos-instituut[9] and Nationaal Vergiftigingen Informatie Centrum[10] (NVIC), describing incidents of strokes after an increased use of the closely related analogue 4-FA, and there is no reason this does not apply to 4-FMA as well. In addition to the common amphetamine-like effects (agitation, anxiety, tachycardia, hypertension, chest pain et al.), serious cardio- and cerebrovascular complications have been reported, including rhythm (sinus arrhythmia, ventricular extrasystoles (bigeminy), conduction disturbances) and acute cardiac failure. Although a causal relationship has not been confirmed, when presented with a severe headache and lateralization after 4-FA usage, a medical evaluation at an emergency department should be conducted immediately. [11]

The toxicity and long-term health effects of recreational 4-FMA use has not been studied in any scientific context and the exact toxic dosage is unknown. This is because 4-FMA has very little history of human usage. Anecdotal evidence suggests that there do not seem to be any negative health effects attributed to simply trying this drug at low to moderate doses by itself and using it sparingly (but nothing can be completely guaranteed).

The LD50 (mouse; i.p.) of 4-FMA is unknown. While 4-FA does not cause long-lasting depletion of brain serotonin unlike MDMA or 4-FA's analogs 4-CA and 4-BA, it is unknown whether this also applies to 4-FMA as well.

4-FMA is reported to be particularly caustic in comparison to other compounds and can, therefore, cause chemical burns within the nasal passage and throat if it is insufflated.

It is strongly recommended that one use harm reduction practices when using this substance.

Tolerance and addiction potential

As with other stimulants, the chronic use of 4-FMA can be considered moderately addictive with a high potential for abuse and is capable of causing psychological dependence among certain users. When addiction has developed, cravings and withdrawal effects may occur if a person suddenly stops their usage.

Tolerance to many of the effects of 4-FMA develops with prolonged and repeated use. This results in users having to administer increasingly large doses to achieve the same effects. After that, it takes about 3 - 7 days for the tolerance to be reduced to half and 1 - 2 weeks to be back at baseline (in the absence of further consumption). This is how long it takes to reduce the tolerance for the stimulating effects. Tolerance for the entactogenic effects may take a longer period to reduce. 4-FA presents cross-tolerance with all dopaminergic stimulants, meaning that after the consumption of 4-FMA all stimulants will have a reduced effect.


Main article: Stimulant psychosis

Abuse of compounds within the amphetamine chemical class at high dosages for prolonged periods of time can potentially result in a stimulant psychosis that may present with a variety of symptoms (e.g., paranoia, hallucinations, or delusions).[12] A review on treatment for amphetamine, dextroamphetamine, and methamphetamine abuse-induced psychosis states that about 5–15% of users fail to recover completely.[13][14] The same review asserts that, based upon at least one trial, antipsychotic medications effectively resolve the symptoms of acute amphetamine psychosis.[15] Psychosis very rarely arises from therapeutic use.[16][17]

Dangerous interactions

Although many drugs are safe on their own, they can become dangerous and even life-threatening when combined with other substances. The list below contains some common potentially dangerous combinations, but may not include all of them. Certain combinations may be safe in low doses of each but still increase the potential risk of death. Independent research should always be done to ensure that a combination of two or more substances is safe before consumption.

  • 25x-NBOMe/25x-NBOH - Members of the 25x family are highly stimulating and physically straining. Combinations with stimulants should be avoided due to the risk of excessive stimulation. This can result in panic attacks, thought loops, seizures, increased blood pressure, vasoconstriction, and heart failure in extreme cases.
  • Alcohol - Alcohol can be dangerous to combine with stimulants due to the risk of accidental over-intoxication. Stimulants mask the sedative effects of alcohol, which is the main factor people use to assess their degree of intoxication. Once the stimulant wears off, the depressant effects of alcohol are left unopposed, which can result in blackouts and respiratory depression. If combined, one should strictly limit themselves to only drinking a certain amount of alcohol per hour.
  • DXM - Combinations with DXM should be strictly avoided due to DXM's effects on serotonin and dopamine reuptake. This can lead to panic attacks, hypertensive crisis, or serotonin syndrome.
  • MXE - Combinations with MXE may dangerously elevate blood pressure and increase the risk of psychosis.
  • Tramadol - Tramadol lowers the seizure threshold.[18] Combinations with stimulants may further increase this risk.
  • Cocaine - This combination may increase strain on the heart.

Serotonin syndrome risk

Combinations with the following substances can cause dangerously high serotonin levels. Serotonin syndrome requires immediate medical attention and can be fatal if left untreated.

Legal status


This legality section is a stub.

As such, it may contain incomplete or wrong information. You can help by expanding it.

  • Canada: 4-FMA would be considered Schedule I as it is an analogue of Amphetamine.[20]
  • China: As of October 2015 4-FMA is a controlled substance in China.[21]
  • New Zealand: 4-FMA is an amphetamine analogue, so is a Schedule 3 controlled substance in New Zealand.[22]
  • United Kingdom: 4-FMA is a Class A drug under the Misuse of Drugs Act. 4-FMA is covered by the 1977 addition to the Misuse of Drugs Act of 1971.[citation needed]

See also

External links



  1. Machiko Nagashima; Takako Seto; Misako Takahashi; Jin Suzuki; Ichirou Yasuda (2006). "Spectrum Data of the 3rd Governor-designated Drugs and the Analyses of Uncontrolled Drugs Purchased" (PDF). Annu. Rep. Tokyo Metr. Inst. Public Health. 57: 109–113.
  2. The effects of non-medically used psychoactive drugs on monoamine neurotransmission in rat brain (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/17223101
  3. Isomeric fluoro-methoxy-phenylalkylamines: a new series of controlled-substance analogues (designer drugs). (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/15639609
  4. https://www.ncbi.nlm.nih.gov/pubmed/25624004 | Monoamine transporter and receptor interaction profiles of novel psychoactive substances: para-halogenated amphetamines and pyrovalerone cathinones.
  5. http://www.sciencedirect.com/science/article/pii/0028390875900994 | Comparison of 4-chloro-, 4-bromo-and 4-fluoroamphetamine in rats: drug levels in brain and effects on brain serotonin metabolism
  6. http://www.sciencedirect.com/science/article/pii/S0014299906013811
  7. http://www.sciencedirect.com/science/article/pii/S0014299906013811 | The effects of non-medically used psychoactive drugs on monoamine neurotransmission in rat brain
  8. 4-fluoromethamphetamine (Reddit) | https://www.reddit.com/r/researchchemicals/comments/57fpu3/4fma_short_response/
  9. https://www.trimbos.nl/
  10. https://www.vergiftigingen.info/
  11. https://psychonautwiki.org/wiki/File:Behandeling-4-fa-intoxicatie.pdf
  12. Treatment for amphetamine psychosis | [1]
  13. Treatment for amphetamine psychosis | [2]
  14. Hofmann FG (1983). A Handbook on Drug and Alcohol Abuse: The Biomedical Aspects (2nd ed.). New York: Oxford University Press. p. 329. ISBN 9780195030570.
  15. Treatment for amphetamine psychosis | [3]
  16. Stimulant Misuse: Strategies to Manage a Growing Problem | http://www.acha.org/prof_dev/ADHD_docs/ADHD_PDprogram_Article2.pdf
  17. http://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021303s026lbl.pdf
  18. Talaie, H., Panahandeh, R., Fayaznouri, M. R., Asadi, Z., & Abdollahi, M. (2009). Dose-independent occurrence of seizure with tramadol. Journal of Medical Toxicology, 5(2), 63-67. https://doi.org/10.1007/BF03161089
  19. Gillman, P. K. (2005). Monoamine oxidase inhibitors, opioid analgesics and serotonin toxicity. British Journal of Anaesthesia, 95(4), 434-441. https://doi.org/10.1093/bja/aei210
  20. Controlled Drugs and Substances Act (S.C. 1996, c. 19) |http://laws-lois.justice.gc.ca/eng/acts/C-38.8/page-12.html#h-28
  21. "关于印发《非药用类麻醉药品和精神药品列管办法》的通知" (in Chinese). China Food and Drug Administration. 27 September 2015. Retrieved 1 October 2015. 
  22. http://www.legislation.govt.nz/act/public/1975/0116/latest/whole.html#DLM436576